#include <iostream>
#include <stdlib.h>

using namespace std;

class Box 
{
    public:
        Box(int h=10,int w=10,int len=10);
        int volume();
    private:
        int height;
        int width;
        int length;
};

Box::Box(int h,int w,int len)
{
    height = h;
    width = w;
    length = len;
}

int Box::volume()
{
    return height*width*length;
}

int main()
{
    Box box1;
    cout<<"The volume of box1 is:"<<box1.volume()<<endl;
    Box box2(15);
    cout<<"The volume of box1 is:"<<box2.volume()<<endl;
    Box box3(15,30);
    cout<<"The volume of box1 is:"<<box3.volume()<<endl;
    Box box4(15,30,20);
    cout<<"The volume of box1 is:"<<box4.volume()<<endl;
    return 0;
}